proof

The word “proof” means evidence or facts that show something is true. In plain terms, evidence that something is true, or a test version of something before it's finalized.

“Proof” is pronounced proof (/pɹuf/ in IPA).

Here is “proof” used in a sentence: “The receipt is proof that she paid for the item.”

Depending on how it is used, “proof” can be a noun, an adjective and a verb.

The word “proof” comes from Late Latin. From Old French prove, from Late Latin proba ("a proof"), from Latin probō ("to test, to prove"). A doublet of probe.

“Proof” is a fairly common word in modern English, usually learned at around the B1 level.

“Proof” has 6 distinct senses listed in this dictionary. The most common is: evidence or facts that show something is true.

Evidence is any information that supports a conclusion, while proof is enough evidence to establish something as true beyond reasonable doubt. In short, evidence points toward a conclusion; proof settles it. A single clue is evidence, but a full, convincing case amounts to proof.

The burden of proof is the responsibility to prove a claim rather than assuming it. In law, it usually falls on the person making an accusation — the prosecution must prove guilt, not the accused prove innocence. More broadly, whoever asserts something is expected to back it up.

Proof takes different forms by field. Legal proof relies on testimony and physical evidence; scientific proof rests on repeatable experiments and data; mathematical proof uses pure logic to show a statement must be true. Everyday proof is simpler — documents or facts that confirm a claim.

A receipt is proof of purchase, a passport is proof of identity, and a mathematical demonstration is proof that a statement always holds. In each case the item or argument does not merely suggest something is true — it establishes it firmly enough to remove reasonable doubt.